1. Field of the Invention
This invention relates to a photosensitive composition. More particularly, it relates to a photosensitive composition which is able to provide a printing plate excellent in chemical resistance and printing durability.
2. Description of the Prior Art
As a typical class of photosensitive polymers, there are known polymers having ##STR3## groups in the main chain thereof. The polymers of this class are prepared by condensation reaction of dicarboxylic acids such as phenylenediacrylic acid, carboxycinnamic acid and chalconedicarboxylic acid and glycols such as ethylene glycol, propylene glycol, butylene glycol, hexamethylene glycol, diethylene glycol and triethylene glycol. However, the polymers containing the glycols of the above-mentioned type show very high sensitivity but exhibit a disadvantageously low chemical resistance. The polymers are apt to be swollen with petroleum hydrocarbon solvents and are gradually worn out by a frictional force. Since petroleum hydrocarbons are usually employed as a solvent for printing ink, it is difficult to make a printing plate of excellent printing durability from these polymers.